How long did it take you to finish? Did you go on a marathon session? I like to play games a little bit at a time. The youtube gameplay vids look awesome. Steampunk style. I don't like the gore I seen. Seems all sunny, until you see the gameplay. Just not my thing.
It was about 11 hours (over two days) but I did a lot of exploring. If you rush through expect somewhere between 8 and 9 depending on how much you die.
As for the gore I'd say it's actually kind of player dependent. I didn't really notice anything to off the wall except for the initial melee battle at the beginning of the game. The executions with the melee weapon are quite brutal but you really don't have to do any of them save for the first one or two at the beginning.